n,m,Q=map(int,input().split())
p=[tuple(map(int,input().split())) for i in range(Q)]
p.sort()
X=Q+1
q=[X]*(Q+2)
from bisect import bisect_left
for _,y in p:
	q[bisect_left(q,y)]=y
for i in range(Q+2):
	if q[i]==X:
		print(i)
		exit()